I am looking for a web service (if not a script which I could run through cron) to monitor a specific part of a webpage (which I could filter with XPath or something similar) and output the difference.

I know there are services that track changes in webpages (some covered here or here), but often, a sidebar of a page is dynamic (ie: updated on latest posts) which would often trigger false positives, so I'd be looking for something more specific.

Some time ago I did something similar on my own with cron and php that would store a hash of the page in a database, but I'm sure there must be something out there with a more elegant solution.


http://femtoo.com is pretty good, includes XPath/CSS Selector support. Has a free account option which might suffice.

  • Looks neat... but no RSS option for notification?? Well, at least the callback option may be used by yahoo pipes or similar services. Or we could use the email option and then a service like emails2rss to convert the notification into RSS. (Of course, assuming the OP would like an RSS feed. I would.) – waldyrious Jan 3 '13 at 18:48

Looks like Yahoo Pipes is what you need. They even recently covered the XPath Fetch Page module on their blog. You'll probably find a detailed module for tracking changes on a web page already made by someone, to which you can just plug in the site address and maybe a few other parameters. You can browse/search existing modules here: http://pipes.yahoo.com/pipes/pipes.popular

  • 1
    I am familiar with their XPath fetch module, I just don't know how would I track changes, Pipes doesn't (does it?) have a buffer/memory so I can compare the present against a previous state. – pax Sep 13 '12 at 22:43
  • Good question. I haven't experimented much with Pipes so I don't have a definitive answer but I'm afraid they don't support such a mechanism for storing data. Maybe someone more knowledgeable will chime in with more useful insight. – waldyrious Sep 13 '12 at 23:01

Check Your Notifier, a Chrome extension.

It monitors specific values on pages using CSS selectors.


maybe a simplier solution for you is the firefox browser-addon Update scanner.

You can't filter by XPath, but you can set the amount of letters that should be scanned and recognised as an real update: for example if you set it to 50 letters, all changes on the page under 50 letters will be ignored.

And of course you can set the checking interval manually. The changes in the page will be highlighted yellow in a nice overview.


For the people who like me stumble upon this in the future - I found a wonderful online service that tracks website changes: http:/neowatcher.com/en/. It is not for one or two pages, rather for tracing content changes on large websites. Ideal for online store admins (like me) to watch their competitors, for web studios to control subcontrators' contributions, and for SEO guys to make sure their clients adhere to the guidelines, you name it. The monthly service fees start with EUR 10, and that amount is just too low when you see the list of features. Gosh, they even create screenshots for changes! And the guys create the regex for you to include only the things that you want and avoid dynamic stuff.

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